Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
  • C07C227/38—Separation; Purification; Stabilisation; Use of additives
  • C07C227/40—Separation; Purification
  • C07C227/42—Crystallisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C229/00—Compounds containing amino and carboxyl groups bound to the same carbon skeleton
  • C07C229/52—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to carbon atoms of six-membered aromatic rings of the same carbon skeleton

Definitions

• the present invention relates to a process for the solidification of hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate (INCI diethylamino hydroxybenzoyl hexyl benzoate, DHHB), wherein the process comprises a steps (a) of applying a shear rate of 800 s 1 or more to liquid hexyl 2- [4-(diethylamino)-2-hydroxybenzoyl]benzoate and (b) adding seed crystals of hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate.
• Hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate also referred to as DHHB
• DHHB is an UV-A filter belonging to the group of benzophenone derivatives. It is sold under the tradename Uvinul A Plus by BASF. It has a melting point of about 54 °C.
• the present invention relates in a first aspect to a process for the solidification of hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate (INCI diethylamino hydroxybenzoyl hexyl benzoate, DHHB), wherein the process comprises the step of (a) applying a shear rate of 800 s 1 or more to liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate and (b) adding seed crystals of hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate, while applying the shear rate of step (a).
• a shear rate of 800 s 1 or more to liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate
• a shear rate of the process of the first aspect are described in further detail. It is to be understood that each preferred embodiment is relevant on
• the liquid hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl] benzoate is provided as a melt, which preferably has a temperature from more than about 54 to about 70 °C, preferably from more than about 54 to about 65 °C, or as a subcooled melt, which preferably has a temperature from about 15 to about 54 °C, preferably from about 20 to about 52 °C.
• the applied shear rate is 900 s 1 or more, preferably 1000 s 1 or more and/or wherein the shear rate is obtained by stirring the melt or subcooled at a stirring speed of 50 to 600 rpm, preferably of 90 to 500 rpm, preferably of 100 to 250 rpm.
• the temperature of the hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate to be solidified in step (b) is from about 15 to about 54 °C, preferably from about 25 to about 52 °C.
• step (b) from 0.0001 to 0.1 g, preferably from 0.0005 to 0.05 g, more preferably from 0.001 to 0.03 g, of seed crystals are added per 1 g of the hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate to be solidified melt and/or the seed crystals have a particle size, determined according to sieve analysis, of less than 100000 pm, preferably from 1 to 10000 pm, more preferably from 5 to 5000 pm.
• step (a) is performed in an apparatus, preferably selected from the group consisting of an extruder, a scraped surface heat exchanger, a cooling disc crystallizer, or a stirred vessel, preferably with scraping agitator, which is cooled to a temperature of less than about 54 °C, preferably about 40 °C or less.
• step (a) is performed in a scraped surface heat exchanger and the process further comprises the steps of
• step (i-2) feeding the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate obtained in step (i-1) into a scraped surface heat exchanger, followed by step (a), wherein the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate is stirred by the scraper.
• step (i-1) a temperature of more than about 54 °C is applied and/or step (i-2) is performed under heating of the feed to a temperature of more than about 54 °C and/or the temperature in the scraped surface heat exchanger is less than about 54 °C.
• step (b) provides the hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate in the form of solidified strands.
• step (b) provides the hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate in the form of a melt suspension, which is solidified by the further steps of (c) cooling the melt suspension on a maturing belt, preferably a cooling belt, or on a drum flaker at a temperature of less than about 54 °C, preferably less than about 40 °C to obtain a solidified melt and
• step (b) provides the hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate in the form of a melt suspension, which is solidified by a further step of
• a cooling belt is applied and the cooling belt comprises at least one cooling zone, preferably wherein the at least one cooling zone is in the temperature range from about 0 to about 40 °C, more preferably from about 10 to about 38 °C, and in particular from about 20 to about 35 °C.
• the cooling belt comprises at least two cooling zones, preferably wherein the temperature of the first cooling zone is higher than the temperature of the second cooling zone, more preferably wherein the first cooling zone is in the temperature range from about 15 to about 40 °C and the second cooling zone is in the temperature range from about 5 to about 30 °C.
• the process is performed as a continuous process, wherein the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate is continuously fed into the scraped surface heat exchanger and the hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate is continuously collected from the scraped surface heat exchanger in the form of solidified strands or in the form of a melt suspension.
• the present invention relates to solidified hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate in the form of pourable or flowable particles having a particle size of less than 30 mm, preferably of more than 5 to 30 mm, pastilles having a particle size of less than 30 mm, preferably of more than 5 to 30 mm, or flakes having a particle size of less than 150 mm, preferably of 1 to 100 mm.
• liquid or flowable particles refers to any solid form being able to be poured or granulated and which is safe and easy to handle by the processor (e.g. having reduced electrostatic properties when compared to powder).
• pastilles is a subtype of the pourable or flowable particles, which preferably are hemispherical structures. Pastilles are preferably obtained via the still liquid melt or melt suspension, which can be portioned into small drops and be placed onto the flat surface such that said pastilles are formed. After the melt or melt suspension has crystallized out, the pastilles can be removed and bottled.
• the term “flakes” refers to a specific solid form, which can be obtained by pouring the still liquid melt or melt suspension onto a flat surface, preferably wherein the obtained layer has a thickness of 0.1 to 10 mm, more preferably of 0.2 to 8 mm or of 0.2 to 5 mm or of 0.2 to 2 mm. After the melt or melt suspension has crystallized out, the solid layer is removed from the plane as is customary and bottled, the thin layer usually being comminuted to a desired flake size by breakage.
• the production process of pourable or flowable particles, pastilles, and flakes can take place discontinuously (batch process) or continuously, where, in a continuous method, a continuously circulating steel belt, for example, can be used as mold for the purposes of the present invention.
• the present invention relates in one embodiment to a process for the solidification of hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate (INCI diethylamino hydroxybenzoyl hexyl benzoate, DHHB), wherein the process comprises the step of
• step (b) adding seed crystals of hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate, while applying the shear rate of step (a).
• liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate is provided as a melt or a subcooled melt.
• Hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate has a melting point of about 54 °C.
• the melting point may vary depending on potential impurities. Therefore, it is to be understood that when referring to the temperature values of the process according to the present invention it is referred to said temperature value ⁇ 2 °C, preferably ⁇ 1 °C.
• ⁇ 2 °C preferably ⁇ 1 °C.
• a temperature range of 54 °C ⁇ 2 °C preferably ⁇ 1 °C.
• the melt has a temperature from more than about 54 to about 70 °C, preferably from more than about 54 to about 65 °C.
• the subcooled melt has a temperature from about 15 to about 54 ° C, preferably from about 20 to about 52 °C.
• the applied shear rate is 900 s 1 or more, preferably 1000 s 1 or more, more preferably 1500 s 1 or more, still more preferably 2000 s 1 or more, and in particular 5000 S 1 or more.
• Preferred shear rates are in the range of from 800 to 100000 s 1 , preferably from 900 to 50000 s 1 , more preferably from 1000 to 30000 s 1 .
• the applied shear rate is in the range of from 800 to 50000 s 1 , preferably from 900 to 30000 s ⁇ 1 , and in particular from 900 to 20000 s 1 .
• shear rate refers to the rate at which progressive shearing deformation is applied to the liquid DHHB.
• the melt or subcooled melt is stirred at a stirring speed of more than 50 rpm, more preferably more than 80 rpm, and in particular more than 100 rpm. It is also preferred that the melt or subcooled melt is stirred at a stirring speed of 50 to 600 rpm, preferably of 80 to 500 rpm, more preferably of 100 to 250 rpm.
• the high shear rate is obtained by stirring the melt or subcooled at a stirring speed of 50 to 600 rpm, preferably of 80 to 500 rpm, preferably of 100 to 250 rpm.
• the seed crystals are added at a temperature from about 30 to about 60 °C, more preferably from about 35 to about 55 °C, and still more preferably from about 40 to less than about 54 °C.
• the temperature of the hexyl 2- [4-(diethylamino)-2-hydroxybenzoyl]benzoate to be solidified is kept in the range from about 15 to less than about 54 °C, preferably from about 25 to about 52 °C.
• step (b) from 0.0001 to 0.1 g, preferably from 0.0005 to 0.05 g, more preferably from 0.001 to 0.03 g, of seed crystals are added per 1 g of the hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate to be solidified.
• the seed crystals have a particle size, determined according to sieve analysis, of less than 100000 pm, preferably from 1 to 10000 pm, more preferably from 5 to 5000 pm.
• the determination of the particle size is preferably performed using two sieves, wherein the first sieve has a broader width than the second.
• an amplitude of 1.5 mm is applied and the two sieves are positioned in a Retsch sieve apparatus, wherein the sieve having a mesh having the broader width is located at the upper position.
• sieving is conducted. The residues are weighed out after intervals within 1 to 20 minutes in order to validate whether the residues of the three obtained fractions change. In general, the distribution of the three fractions does not change any more after 5 to 10 minutes.
• the determination of the particle size is performed using two sieves, wherein the first sieve has a mesh width of 5 mm and the second sieve has a mesh width of 0.1 mm.
• an amplitude of 1.5 mm is applied and the two sieves are positioned in a Retsch sieve apparatus, wherein the sieve having a mesh width of 5 mm is located at the upper position.
• sieving is conducted.
• the residues are weighed out after intervals within 1 to 20 minutes in order to validate whether the residues of the three obtained fractions change. In general, the distribution of the three fractions does not change any more after 5 to 10 minutes.
• the first fraction comprises particles having a particle size of less than 0.1 mm
• the second fraction comprises particles having a particle size of 0.1 to 5 mm
• the third fraction comprises particles having a particle size of more than 5 mm.
• the step (a) is performed in an apparatus, preferably selected from the group consisting of an extruder, a scraped surface heat exchanger, a cooling disc crystallizer, or a stirred vessel, preferably with scraping agitator, which is cooled to a temperature of less than about 54 °C, preferably about 40 °C or less.
• the process is a continuous process.
• a continuously operated process comprises using a scraped surface heat exchanger and a storage vessel where the DHHB melt can be stored above its melt temperature.
• a scraped surface heat exchanger which can be fed with DHHB melt from the storage vessel, is used to generate a melt suspension.
• liquid DHHB is cooled down by means of a cooled internal surface (also referred to as scraped surface) and stirred by the scraper.
• seed crystals are added. After the onset of crystallization, crystals are generated on a cold internal surface and scraped off by means of a scraper comprised in the scraped surface heat exchanger.
• the generated melt suspension is fed back to the storage vessel until the desired solid content in the generated melt suspension is reached.
• an increase of the turbidity of the DHHB melt suspension can be observed (e.g. via the signal of the turbidity probe).
• a color change from brownish to bright yellow can be observed when crystallization starts significantly.
• the melt suspension can be continuously applied to a maturing belt, preferably a cooling belt (more preferably with multiple temperature zones).
• step (a) is performed in a scraped surface heat exchanger and the process further comprises the steps of
• step (i-2) feeding the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate obtained in step (i-1) into a scraped surface heat exchanger, followed by step (a), wherein the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate is stirred by the scraper.
• step (i-1) a temperature of more than about 54 °C is applied. It is also preferred that in step (i-1), a temperature of from more than about 54 to about 70 °C, more preferably from more than about 54 to about 65 °C is applied.
• step (i-2) is performed under heating of the feed to a temperature of more than about 54 °C. It is also preferred that step (i-2) is performed under heating of the feed to a temperature of from more than about 54 to about 70 °C, more preferably from more than about 54 to about 65 °C.
• the temperature in the scraped surface heat exchanger is less than about 54 °C, preferably less than about 52 °C.
• the internal surface of the scraped surface heat exchanger has a temperature of less than about 50 °C, more preferably less than about 40 °C, still more preferably less than about 30 °C, and in particular less than about 20 °C. It is also preferred that the internal surface of the scraped surface heat exchanger has a temperature of from about 1 to about 50 °C, more preferably from about 2 to about 40 °C, still more preferably from about 3 to about 30 °C, and in particular from about 5 to about 20 °C.
• the scraped surface heat exchanger is cooled via its internal surface. Therefore, when referred to the temperature in the scraped surface heat exchanger, it is referred to the approximate temperature of the melt/melt suspension, which is cooled via the cooled internal surface. When referred to the temperature of the internal surface it is referred to the temperate of the internal surface of the scraped surface heat exchanger.
• step (i-1) a temperature of more than about 54 °C is applied, the step (i-2) is performed under heating of the feed to a temperature of more than about 54 °C and the temperature in the scraped surface heat exchanger is less than about 54 °C.
• step (a) is performed in a stirred vessel and the process further comprises the steps of
• step (ii-2) cooling, preferably while stirring, the liquid hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate obtained in step (ii-1) to obtain a subcooled melt of hexyl 2-[4- (diethylamino)-2-hydroxybenzoyl]benzoate, (ii-3) feeding the subcooled melt of hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate into a stirred vessel, followed by step (a).
• step (ii-1) a temperature of more than about 54 °C is applied. It is also preferred that in step (ii-1), a temperature of from more than about 54 to about 70 °C, more preferably from more than about 54 to about 65 °C is applied.
• the subcooled melt has a temperature of less than about 54 °C. It is also preferred that in step (ii-2), the subcooled melt has a temperature in the range from about 15 to about 54 °C, preferably from about 20 to about 52 °C.
• step (ii-1) a temperature of more than about 54 °C is applied and in step (ii-2), the subcooled melt has a temperature of less than about 54 °C.
• step (b) provides a melt suspension.
• melt suspension denotes a melt comprising solids.
• a melt suspension of DHHB comprises DHHB in liquid, i.e. molten form, and in solid form.
• the melt suspension provided by step (b) may be poured on any suitable container in order to allow the melt suspension to further cool and solidify.
• step (b) provides the hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate in the form of solidified strands.
• step (b) provides the hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate in the form of a melt suspension, which is solidified by the further steps of
• step (b) provides the hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate in the form of a melt suspension, which is solidified by a further step of
• a cooling belt is applied and the cooling belt comprises at least one cooling zone.
• the at least one cooling zone is in the temperature range from about 0 to about 40 °C, more preferably from about 10 to about 38 °C, and in particular from about 20 to about 35 °C.
• the cooling belt comprises at least two cooling zones, more preferably wherein the temperature of the first cooling zone is higher than the temperature of the second cooling zone.
• the temperature in the first cooling zone is about 5 °C, more preferably about 10 °C, higher than the temperature in the second cooling zone.
• the first cooling zone is in the temperature range from about 15 to about 40 °C, more preferably from about 22 to about 38 °C
• the second cooling zone is in the temperature range from about 5 to about 30 °C, more preferably from about 10 to about 20 °C.
• the process is performed as a continuous process, wherein the liquid hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate is continuously fed into a scraped surface heat exchanger or an extruder and the hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate is continuously collected from the scraped surface heat exchanger or the extruder in the form of solidified strands or in the form of a melt suspension.
• a ripening belt can be used subsequent to the cooling belt.
• the present invention relates to solidified hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate in the form of pourable or flowable particles having a particle size of less than 30 mm, preferably of more than 5 to 30 mm, pastilles having a particle size of less than 30 mm, preferably of more than 5 to 30 mm, or flakes having a particle size of less than 150 mm, preferably of 1 to 100 mm.
• the pourable or flowable particles have a particle size, determined according to sieve analysis, of 0.01 to 30 mm, more preferably of 0.1 to 30 mm, still more preferably of more than 5 to 30 mm, and in particular of 10 to 25 mm.
• Any suitable method for determining the particle size of the pourable or flowable particles may be applied.
• the particle size of the pourable or flowable particles may be determined via sieve analysis.
• the determination of the particle size are performed using two sieves, wherein the first and the second sieves have a mesh width, which is suitable for the determination of e.g. 1 to 30 mm.
• an amplitude of 1.5 mm is applied and the two sieves are positioned in a Retsch sieve apparatus, wherein the sieve having the broader mesh width is located at the upper position. After applying the sample on the upper located sieve, sieving is conducted for 1 to 20 minutes until no change of the distribution of the three fractions is detected.
• the particle size of the pourable or flowable particles may also be determined according to caliper.
• the Fere . of Feret's diameter is decisive for the particle size.
• Sieving is preferably used for of the pourable or flowable particles having a particle size of less than 20 mm, more preferably less than 10, and in particular of 5 mm and less.
• Image analysis or caliper are preferably used for the pourable or flowable particles having a particle size of more than 5 mm, more preferably more than 10 mm.
• the pourable or flowable particles have a bulk density of 0.35 g/ml_ or more, more preferably of 0.35 to 0.5 g/ml_.
• the pastilles have a particle size of 1 to 30mm, more preferably of 2 to 30 mm, still more preferably of more than 5 to 30 mm, and in particular of 6 to 20 mm.
• the particle size of the pastilles may be determined according to image analysis. Therefore, 100 pastilles are randomly selected from the final product. The particle sizes are determined and the average particle diameter is derived therefrom.
• the particle size of the pastilles may also be determined according to caliper.
• the FereW . of Feret's diameter is decisive for the particle size.
• Using the caliper method is preferred for pastilles having a particle size of more than 5 mm.
• the pastilles have a bulk density of 0.35 g/mL or more, more preferably of 0.35 to 0.5 g/mL.
• the flakes have a particle size of 1 to 100 mm, more preferably of 5 to 90 mm, even more preferably of more than 5 to 85 mm, still more preferably of 7 to 80 mm, and in particular of 10 to 80 mm.
• Any suitable method for determining the particle size of the flakes may be applied.
• the particle size of the flakes may be determined according to image analysis. Therefore, 100 flakes are randomly selected from the final product. The particle sizes are determined and the average particle diameter is derived therefrom.
• the particle size of the flakes may also be determined according to caliper.
• the FereW . of Feret's diameter is decisive for the particle size.
• Using the caliper method is preferred for flakes having a particle size of 5 mm and more.
• the flakes have a bulk density of 0.35 g/mL or more, more preferably of 0.35 to 0.5 g/mL.
• Example 6 of EP 2155660 B1 5 kg of DHHB is poured in a 5 L aluminum vessel.
• the melt is stirred by an PTFE propeller stirrer (60 mm diameter), which is stirred by an electrical motor.
• the melt is stirred at 25 °C with a stirring speed of 250 rpm (approximately 1000 s 1 ).
• melt viscosity increases significantly so that stirring is not possible any more.
• First crystals are observed after 5h of stirring. Complete solidification is achieved after 24h.
• Example 3 No Shear Rate with Seeding
• Example 10 of EP 2155660 B1 DHHB seed particles are added to 5kg DHHB melt.
• the melt temperature at which seed particles ( ⁇ 100 pm) are added is about 40°C.
• the DHHB melt is allowed to cool down to room temperature. First crystals are observed after 10 days. Complete solidification is achieved after 2 months. The melt is not stirred during the experiment.
• Inventive Example 1 High Shear Rate (800 s-1 or more) with Seeding
• a scraped surface heat exchanger covering a melt volume of approximately 90L was used in the experiment.
• a melt of DHHB was fed from a storage tank into the scraped surface heat exchanger, where it was cooled down below its melt temperature (i.e. below about 54 °C).
• the stirring speed of the scraper was maintained at 120 rpm throughout the experiment.
• DHHB melt temperature was below 54 °C
• DHHB seed particles were added to the melt.
• DHHB powder of approximately ⁇ 200 pm was used as seed particles. After approximately 2-3h crystallization was observed to start significantly.
• samples of the DHHB melt were taken from the scraped surface heat exchanger (every 30 min). The start of crystallization could be observed visually by eye (increase of turbidity) and an increase of the scraper torque. Also, a color change of the product from brownish to yellow could be observed.
• the melt suspension was poured onto a cooling belt. Depending on the tool used for applying the melt suspension on the cooling belt, DHHB pastilles or a DHHB layer was produced on the cooling belt.
• the cooling belt comprised of two different cooling zones. The first section of the cooling belt length was maintained at 30°C, whereas the second section was maintained at 15°C.
• the obtained pastilles (Inventive Example 1.2) have an average height of 3.5 to 4.5 mm and an average diameter of 7 to 9.5 mm. Hence, their particle size as understood according to the present invention is from 7 to 9.5 mm (i.e. the FereW . ).
• Table 1 Process parameters for the generation of DHHB flakes and pastilles.
• the complete solidification of the DHHB melt suspension can be obtained surprisingly faster when seed crystals are applied in combination with high shear rates.

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• 2022
  • 2022-03-01 WO PCT/EP2022/055089 patent/WO2022184683A1/en active Application Filing
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